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Waves & Signals

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Electroenthusiast

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Hi,
I was just thinking of various types of signals that are used in communication systems. Mostly we use EMWaves for the purpose of communication.
For an example, consider FM/AM, these signals can be grabbed/catched by the Radio whenever the radio is inside a certain boundary (often of a circular type). Same as in the case of a mobile phones.

Whereas, when you consider a TV Remote(Infrares), it travels only in a particular direction.

My question is: How do you visualise the propagation of these signals?
Like, in a mobile network the signal traverses in all direction.
 
Well with EM waves how they propagate depends on the antenna that emits them. However waves are not the same as signals. To visualize how waves move, just go to the beach. :D Im not kidding, think of how water waves move from the bottom of the ocean when there is an earthquake or something.
At least thats how i see it.
 
Hi,


And there is always the great maybe even overly quoted analogy: Throw a pebble into a pool of still water and watch the waves move out from the point where the pebble hit the water. The waves move away in a circular pattern.
Antennas can have other radiation patterns too though.
 
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Hi,


And there is always the great maybe even overly quoted analogy: Throw a pebble into a pool of still water and watch the waves move out from the point where the pebble hit the water. The waves move away in a circular pattern.
Antennas can have other radiation patterns too though.
To continue the water analogy, if you drop the pebble off the side of a boat the waves will tend to move only in a semicircular pattern away from the side. That very roughly shows how directional transmitting antennas work.
 
IR is also an E and M wave, but the wavelength is very short. The longer the wave length the less directional a wave tends to be. A "beam" as in radio beam travels in a more defined direction when the beam witdth is much larger than the wave length. Check out waves in a physics book ( spreading of the beam also applies to sound ) .
 
But somehow if i could see them- if at all those signals were perceptive to our eyes, it would have nice!

Coming back to the 'pebble in water' concept : EM (in Radio)waves travel in all direction in spherical manner. So it should be visualized in 3 Dimension. That was all right, But Again how to visualise in 3D, Making things Complicated https://en.wikipedia.org/wiki/Wave–particle_duality, wave nature/particle nature.
What abt the signals from infrared remotes? Some transmitters are unidirectional, how to visualize them?
 
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But somehow if i could see them- if at all those signals were perceptive to our eyes, it would have nice!

Coming back to the 'pebble in water' concept : EM (in Radio)waves travel in all direction in spherical manner. So it should be visualized in 3 Dimension. That was all right, But Again how to visualise in 3D, Making things Complicated Wave, wave nature/particle nature.
What abt the signals from infrared remotes? Some transmitters are unidirectional, how to visualize them?

According to what I have personally experienced the wave of infrared is no different than that of a light bulb. It is directional limit of visual wavelength. So, anything within the scope of the beam that is obtained by it's receiver or if the beam emitted and or the physical parameter of the remote and construct of the plastic to visual light emission could then maybe be, 180degrees; a little more or less depending on if you have anything diffracting the signal.

If, in a space devoid of diffraction be it particle or other combination of atmospheric absorption and cantilever does not exist. Then if and only if in a sense is void. You could obtain an extraction of the quantity of light required to excite the receiver and it's origin permissible to omission which is relative from the point it was emitted.

Again according to the construct of the remote 180degress + or minus x and y omission.

Edit: If you want to visualize a more perceptive model, think of water and wave the Height and length and width of propagation.
 
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But somehow if i could see them- if at all those signals were perceptive to our eyes, it would have nice!

Coming back to the 'pebble in water' concept : EM (in Radio)waves travel in all direction in spherical manner. So it should be visualized in 3 Dimension. That was all right, But Again how to visualise in 3D, Making things Complicated Wave, wave nature/particle nature.
What abt the signals from infrared remotes? Some transmitters are unidirectional, how to visualize them?

Hi again,

Yes the waves can move out in a spherical pattern in 3d, the pebble in the pond is meant to show how the amplitude varies. You can still apply this to the 3d case if you look at the pond as a slice of the sphere where a line along the pond surface out from the center is the spheres radial line in any direction you care to choose, or the pond surface is a plane intersecting the sphere and passes through the center of the sphere. The point would be that the wave moves out from the center and the intensity of the field decreases the farther out from the center.
 
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